diff --git a/0286-ieee1275-implement-vec5-for-cas-negotiation.patch b/0286-ieee1275-implement-vec5-for-cas-negotiation.patch
new file mode 100644
index 0000000..f9f2170
--- /dev/null
+++ b/0286-ieee1275-implement-vec5-for-cas-negotiation.patch
@@ -0,0 +1,71 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Diego Domingos <diegodo@linux.vnet.ibm.com>
+Date: Thu, 25 Aug 2022 11:37:56 -0400
+Subject: [PATCH] ieee1275: implement vec5 for cas negotiation
+
+As a legacy support, if the vector 5 is not implemented, Power
+Hypervisor will consider the max CPUs as 64 instead 256 currently
+supported during client-architecture-support negotiation.
+
+This patch implements the vector 5 and set the MAX CPUs to 256 while
+setting the others values to 0 (default).
+
+Signed-off-by: Diego Domingos <diegodo@linux.vnet.ibm.com>
+Signed-off-by: Robbie Harwood <rharwood@redhat.com>
+(cherry picked from commit f735c65b6da8a9d4251242b37774e1a517511253)
+---
+ grub-core/kern/ieee1275/init.c | 20 +++++++++++++++++++-
+ 1 file changed, 19 insertions(+), 1 deletion(-)
+
+diff --git a/grub-core/kern/ieee1275/init.c b/grub-core/kern/ieee1275/init.c
+index ef55107467..6a51c9efab 100644
+--- a/grub-core/kern/ieee1275/init.c
++++ b/grub-core/kern/ieee1275/init.c
+@@ -311,6 +311,18 @@ struct option_vector2 {
+   grub_uint8_t max_pft_size;
+ } __attribute__((packed));
+ 
++struct option_vector5 {
++        grub_uint8_t byte1;
++        grub_uint8_t byte2;
++        grub_uint8_t byte3;
++        grub_uint8_t cmo;
++        grub_uint8_t associativity;
++        grub_uint8_t bin_opts;
++        grub_uint8_t micro_checkpoint;
++        grub_uint8_t reserved0;
++        grub_uint32_t max_cpus;
++} __attribute__((packed));
++
+ struct pvr_entry {
+   grub_uint32_t mask;
+   grub_uint32_t entry;
+@@ -329,6 +341,8 @@ struct cas_vector {
+   grub_uint16_t vec3;
+   grub_uint8_t vec4_size;
+   grub_uint16_t vec4;
++  grub_uint8_t vec5_size;
++  struct option_vector5 vec5;
+ } __attribute__((packed));
+ 
+ /* Call ibm,client-architecture-support to try to get more RMA.
+@@ -349,7 +363,7 @@ grub_ieee1275_ibm_cas (void)
+   } args;
+   struct cas_vector vector = {
+     .pvr_list = { { 0x00000000, 0xffffffff } }, /* any processor */
+-    .num_vecs = 4 - 1,
++    .num_vecs = 5 - 1,
+     .vec1_size = 0,
+     .vec1 = 0x80, /* ignore */
+     .vec2_size = 1 + sizeof(struct option_vector2) - 2,
+@@ -360,6 +374,10 @@ grub_ieee1275_ibm_cas (void)
+     .vec3 = 0x00e0, // ask for FP + VMX + DFP but don't halt if unsatisfied
+     .vec4_size = 2 - 1,
+     .vec4 = 0x0001, // set required minimum capacity % to the lowest value
++    .vec5_size = 1 + sizeof(struct option_vector5) - 2,
++    .vec5 = {
++	0, 0, 0, 0, 0, 0, 0, 0, 256
++    }
+   };
+ 
+   INIT_IEEE1275_COMMON (&args.common, "call-method", 3, 2);
diff --git a/grub.patches b/grub.patches
index 7f703a8..81ad803 100644
--- a/grub.patches
+++ b/grub.patches
@@ -283,3 +283,4 @@ Patch0282: 0282-efi-split-allocation-policy-for-kernel-vs-initrd-mem.patch
 Patch0283: 0283-efi-allocate-the-initrd-within-the-bounds-expressed-.patch
 Patch0284: 0284-efi-use-EFI_LOADER_-CODE-DATA-for-kernel-and-initrd-.patch
 Patch0285: 0285-BLS-create-etc-kernel-cmdline-during-mkconfig.patch
+Patch0286: 0286-ieee1275-implement-vec5-for-cas-negotiation.patch
diff --git a/grub2.spec b/grub2.spec
index c6ed41c..711fe9d 100644
--- a/grub2.spec
+++ b/grub2.spec
@@ -14,7 +14,7 @@
 Name:		grub2
 Epoch:		1
 Version:	2.06
-Release:	44%{?dist}
+Release:	45%{?dist}
 Summary:	Bootloader with support for Linux, Multiboot and more
 License:	GPLv3+
 URL:		http://www.gnu.org/software/grub/
@@ -532,6 +532,10 @@ mv ${EFI_HOME}/grub.cfg.stb ${EFI_HOME}/grub.cfg
 %endif
 
 %changelog
+* Thu Aug 25 2022 Robbie Harowod <rharwood@redhat.com> - 2.06-45
+- ieee1275: implement vec5 for cas negotiation
+- Resolves: #2121192
+
 * Mon Aug 15 2022 Robbie Harwood <rharwood@redhat.com> - 2.06-44
 - Skip rpm mtime verification on likely-vfat filesystems
 - Resolves: #2047979